There were several jaw-dropping moments at Sunday night’s UFC on Versus 5 event, the most surprising of which was the news of MMA trainer Shawn Tompkins’ death in Canada, shared by UFC announcers Joe Rogan and Mike Goldberg between fights.

The 37-year-old kickboxer and mixed martial artist passed away in his sleep Sunday. There are few details currently available, and the cause of death is still unknown, pending an autopsy.

Though he hailed from Ontario, Canada, Tompkins spent much of his time in Las Vegas training fighters like Sam Stout, Mark Hominick and John Gunderson. In addition to these younger fighters, Tompkins has helped train MMA veterans Vitor Belfort, Bas Rutten, Randy Couture and Wanderlei Silva. He trained at local gyms all over town including LA Boxing, Xtreme Couture and most recently, the Tapout Training Center.

Despite a 0-4 record in his own professional MMA career, Tompkins’ star was on the rise in the coaching world. In 2009, he was nominated for Coach of the Year at the World Mixed Martial Arts Awards. Though he did not win, being nominated in a category along with coaching greats like Greg Jackson and Mark DellaGrotte was recognition of his status as a trainer.

Tompkins had many memorable experiences cornering his fighters, but one recent battle stands out. Tompkins trained fellow Canadian Mark Hominick for his April title shot against featherweight champ Jose Aldo at UFC 129. Despite massive swelling in his head, Hominick went all five rounds against Aldo, eventually losing by decision. At the end of the fight, Tompkins hugged Hominick like he had he won, acknowledging his tremendous effort.

The coach was in Canada training fighter Chris Horodecki for an upcoming bout when he died.

The outpouring of emotion in the MMA community has been overwhelming. Local fighter John Gunderson said on his Facebook page, “Lost a great friend & mentor today,” and changed his profile picture to one of himself and his former trainer.

Fighter Javier Torres did the same, opting for a shot of Tompkins giving him water between rounds during one of his fights. On his Facebook page, Torres called Tompkins, “my friend, my trainer and partner of wars” and a “legend.”

On his Twitter account, UFC legend Randy Couture said, “Shawn was a mentor and coach to many of us in the MMA world. He will be sorely missed.”

Kerry Hartney, fight matchmaker with the local Tuff-N-Uff organization, said, “I am honored to have known him, and he’s one of the legends of MMA. We lost a warrior, but his legacy will live forever. He was a truly wonderful person with a huge heart.”

The Toronto Sun reports that Hominick said, "I just think the reality is setting in now. We are trying to get our head around this, and we just can't. We're trying to hold it together, but it's so hard."

Local radio personality and MMA commentator Dave Farra had worked with Shawn on many occasions in fights here in Las Vegas and across the country. Farra said, “Shawn was an awesome guy and an awesome trainer. He was always giving 100 percent of himself to other people, and this was evidenced by how close his team and his family are.”

Farra also noted Tompkins’ tendency to go above and beyond for his team. “He was always opening up his home to up and coming fighters in their time of need, and now some of them are contenders to world championships. Shawn just loved what he did and you could tell.”

Tompkin’s compassion went beyond the ropes of the training ring, as well. In October 2009, he came to the aid of troubled fighter Junie Browning after Browning attempted suicide. When asked about the incident, Tompkins revealed, “People have been questioning and asking about my openness to it, and you know what, I am more than a trainer. It is a commitment. Everybody here is a human being, so if I get a call that something like that is happening, I’m going to go for anybody.”

The date for a memorial service in Las Vegas is yet to be determined, but more details will be announced at amrgroup.tv. A guestbook is available for those wishing to express their sympathies to the Tompkins family, and the Shawn Tompkins Memorial Fund has been established. Those wishing to contribute may contact TeamTompkins@ShogunMMA.com.